1. Field of the Invention
The present invention pertains to a device making it possible to conveniently take up or collect a fluid or liquid which is present on a flexible surface, and more particularly to a device for taking up a fluid or liquid present on an epithelium of an organism. The device of the invention is, in particular, intended to take up or sample sweat, secretion, tissue fluid, sucked exudate or the like exuded or secreted on the skin.
2. Related Art
A conventional device for taking up a body fluid generally has such a construction that blood, for example, is taken up by puncturing the skin with a hollow injection needle. In particular, the measurement of blood sugar for patients suffering from diabetes using an abbreviated blood sugar-measuring instrument is effected with the blood taken up by puncturing a lancet into the skin of a finger tip or the like of the patient. Inasmuch as the reduction of the quantity of blood required for the measurement, the miniaturization of the instrument as well as the simplification of the procedural method of use have been achieved by this abbreviated blood sugar-measuring instrument, it is now possible to effect such measurement outside hospitals, such as at home.
However, inasmuch as the sampling of blood, even of a small quantity, is required for the measurement of blood, danger to infection and mental burden caused by pain are accompanied for the patients.
In recent years, there is a demand on safer and easier procedures to solve these problems. As result, a method of taking up blood in a quantity of 1 microliter or less by utilizing a micro-machining technique or the like is proposed, and attention has been paid to body fluids other than blood, such as sweat, exudate or the like, as a fluid to be measured.
Such a body fluid can be taken up only in a small quantity of a microliter order, and vaporizes immediately when left on the skin. Therefore, it is necessary for a device of the type which takes up such a body fluid to have a function of taking up the body fluid as quickly and conveniently as possible.
A conventional device for taking up a body fluid present on the skin is described, for example, in Japanese Utility Model Application, Laid-Open No. Hei 1-49597, and is depicted in FIG. 8. This conventional device is constructed so as to take up a body fluid 29 into a fluid-reservoir 32 by sucking the skin 35 under pressure through a sucking opening 36. In this device, a spacer 26 is interposed between the sucking opening 36 and the skin surface in order to prevent the intimate contact of the sucking opening 36 against the skin 35, and the delivery of the body fluid 29 towards the outside of the device is conducted by closing an electromagnetic valve 33 arranged between the fluid-reservoir 32 and the sucking opening 36 and subsequently opening an openable lid 27.
However, the conventional device depicted in FIG. 8 has the following disadvantages:
First, the operation of the device requires a considerable number of procedural steps, resulting in inconvenience in manipulation. More specifically, this device requires an operation of taking up the body fluid into the fluid-reservoir by suction, an operation of closing the electromagnetic valve and an operation of delivering the body fluid by opening the lid.
Second, since the device uses, for example, an electromagnetic valve, the number of parts required for the assembly is great, resulting in an increased manufacturing cost. As a result, the device cannot be of a disposable type. Furthermore, since it cannot be of a disposable type, a very laborious operation of washing the device is additionally required.
Third, it is not possible to reduce dead volume. More specifically, since the device includes an openable valve, such as an electromagnetic valve, at a fluid passage between the skin sucking opening and the fluid-reservoir, the dead volume or space is large and not negligible for the delivery of a small quantity of fluid. In addition, since the body fluid adheres to the wall surface of the fluid-reservoir, it is not possible to take out the taken-up body fluid completely.